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Mars may be more hospitable to life - including human explorers of the future - than had been feared, according to new research using information sent back both from NASA's robot rover Curiosity and from orbiters circling the red planet.

Apart from atmosphere and possible planetary magnetic fields (like those which make Earth so hospitable), there's another major way in which a planet can protect those on its surface from the dangerous levels of radiation which permeate space at all times and occasionally - for instance during major solar storms - surge to fatal levels.

A planet naturally blocks out half the sky and its background cosmic rays for anyone standing on its surface. Around half the time this will include the Sun, which is the source of most of the dangerous radiation in the solar system.

But that still leaves a lot of potential for explorers to be hit by harmful radiation during solar storms and so on. Shielding materials would necessarily be heavy, and thus probably impractical to send along on an interplanetary trip.

Another major issue for Mars explorers is likely to be availability of water. If water can be obtained locally, this solves several problems: it can be used to make rocket fuel and/or oxidiser, meaning that far less need be hauled in across the immense journey from Earth and hugely cutting travel costs. Oxygen from water can also be breathed, and naturally the water itself can also help sustain the lives of the astronauts themselves and the probable hydroponic plants they will be growing for food.

Given all of this, then, it's good news to hear on the science wires of new research indicating that there may be more water about on Mars than had seemed to be the case from orbital imagery. An announcement from Gothenburg uni has this to say:

The process of analysing satellite images from Mars has been combined with similar studies of an arctic environment in Svalbard. Despite the fact that Svalbard is considerably warmer than Mars, the arctic landscape shows a number of striking similarities to certain parts of Mars.

One important common feature is the presence of permafrost and frozen subsurface water.

Having studied hundreds of gullies on Mars and compared these with Svalbard, the researchers found evidence that the gullies on Mars were likely formed by melting snow and water erosion. Field work has supplemented the interpretation of aerial images.

"One important insight we have gained is that, despite the high image resolution for both Svalbard and Mars, the camera can’t capture everything," explains Dr Andreas Johnsson. "What appears to be fine-grained sediment on an aerial image of Svalbard can actually turn out to be a very rocky area which has implications for certain types of landforms. It’s important to bear this in mind when studying images of Mars.”

So, not only is there more water than had been thought, some areas of Mars may be more like Svalbard than they seem from space. As opposed to red sand, they actually be rocky - and, like Svalbard, they may have rock caves formed by snow and ice in the past, suitable for human habitation.

Caves would make excellent shelters from radiation storms and indeed radiation in general, so their presence or absence is always of great interest to planetary exploration. And, of course, if water is more common then alien life may also be more likely.

The Gothenburg statement goes on to add:

The existence of liquid water is a vital component if life on Mars is to be possible.

“Research on Earth has shown that organisms can survive in extreme cold environments with limited access to liquid water,” continues Dr Johnsson. “Studying various areas on Mars therefore enables us to investigate whether there could be environments with conditions capable of supporting life.” ®